Obesity and stress are highly comorbid and both increase risk for cardiovascular disease (CVD). Stress is associated with disinhibited eating, junk food consumption and low consumption of produce and whole grains. Both stress and stress-induced eating are not only associated with obesity but also predict worst outcomes in lifestyle interventions. In addition to diet and physical activity, both stress and stress-induced eating should be targeted in interventions obese adults to maximize weight loss and CVD risk reduction; however, this makes for an intensive intervention. Technology could be leveraged to reduce intervention burden while still addressing more complicated patient issues by collecting and compiling patient data to inform clinician decision making and directly delivering intervention strategies. The purpose of this proposal is to develop and test the feasibility and proof-of-concept of RELAX Application Suite (AS), a mobile-, and cloud- and web-based companion to a lifestyle intervention for obese individuals. RELAX-AS includes RELAX-app and RELAX-web. RELAX-app is a patient-facing mobile application that will be linked to Microsoft Health Vault, a cloud-based platform that allows for secure access of health data online. RELAX-app will include self-monitoring (diet, exercise, stress, stress-induced eating); automated feedback via easy-to-interpret visual displays and feedback reports on the amount, timing, context, and relationship between target behaviors; and self-guided stress management features that are prompted when stress ratings are elevated. RELAX-web is a web-based application for clinicians to access the patient's information in the form of easily digestible visual displays and feedback reports to increase the efficiency of their counseling. Our goal is to use RELAX-AS to create an intervention delivery model that reduces both weight and stress with half the visits of traditional lifestyle interventions. We propose a 3-year study that includes 3 phases: Requirements Gathering/Development, Usability Testing/Pre-Pilot, and Pilot. Requirements Gathering/Development work will focus on the iterative development of visual displays, feedback messages, and mobile-delivered stress reduction strategies among users and clinicians. In the Usability Testing/Pre-pilot phase we will examine usability of RELAX-AS in both members of the target population and clinicians using an abbreviated 4-week pre-pilot intervention. In the Pilot phase, we will randomize obese adults to 3 conditions: RELAX-AS, a generic diet/exercise application system, or no technology. All conditions will receive brief weight loss counseling. Feasibility outcomes will be usage of app features, acceptability, adherence, clinician time, burden, retention, time and cost. Exploratory outcomes include changes in weight, stress, and stress-induced eating. This work will prepare us for a 2-arm efficacy trial comparing RELAX-AS with a brief lifestyle intervention to a brief lifestyle intervention alone on weight, stress, and stress eating.